When measuring the depth of a body of running or standing water, or when making other level or distance measurements such as measuring snow depth in the mountains, measurement devices (sensors) which are powered by means of a battery or rechargeable battery are often used, since supplying power via a cable is usually not possible or at least not provided.
In order to be able to use the limited energy available over as long a time period as possible, the times between two successive measurements can be increased. It is thus usually sufficient to measure the depth of a river once a day. However, in this case, rapid depth changes are, in some circumstances, only measured and reported to the control station after a delay of several hours.